Preparation process of superfine high-dispersion cobalt oxide

Abstract

The invention discloses a preparation process of superfine high-dispersion cobalt oxide, and belongs to the technical field of cobalt oxide preparation. Comprising the following steps: S1, mixing cobalt nitrate hexahydrate and deionized water, and stirring for 15-20 minutes to obtain a cobalt nitrate solution; s2, taking the cobalt nitrate solution, adding a dispersing agent, stirring for 30-40 min, adjusting the pH value to 9.2-9.5, aging at 5-10 DEG C for 24 h, carrying out centrifugal separation, taking a solid phase, and washing to obtain a material A; s3, putting the material A into a 100mL high-pressure kettle, adding absolute ethyl alcohol and n-butyl alcohol, stirring for 30-40 minutes, purging the high-pressure kettle with nitrogen to remove air in the kettle, sealing, pressurizing, heating and stirring for 30-40 minutes, discharging fluid in the kettle, and cooling a solid-phase material in the kettle to obtain a material B; and S4, putting the material B into a muffle furnace, calcining, grinding and sieving to obtain the superfine cobalt oxide with high dispersity.

Description

Technical Field

[0001] The invention belongs to the technical field of cobalt oxide preparation, and in particular relates to a preparation process of ultrafine and highly dispersed cobalt oxide. Background Art

[0002] Cobalt oxide plays an indispensable role in many fields such as lithium-ion batteries, glass, ceramics, cemented carbide and electronic materials. As a raw material for the preparation of key products such as lithium cobalt oxide and electronic paste, cobalt oxide has extremely low requirements for impurity content and also has extremely high standards for physical properties such as morphology, particle size and distribution. Lithium-ion batteries have attracted much attention in the market due to their many advantages such as high voltage, high energy density, long cycle life and environmental friendliness.

[0003] In recent years, with the continuous surge in demand for small portable power sources, new vitality has been injected into the development of the lithium-ion battery industry. The rapid development of this industry has further promoted the research and development and production of cobalt-based positive electrode materials such as lithium cobalt oxide, lithium nickel cobalt oxide, and lithium nickel cobalt manganese oxide. Therefore, the demand for cobalt-based positive electrode materials for lithium-ion batteries has also shown a rapid growth trend, among which cobalt oxide has become the main raw material for the preparation of these positive electrode materials.

[0004] There are many methods for preparing cobalt oxide, including solid phase method, gas phase method, liquid phase method (such as chemical precipitation method, solvent thermal method, hydrothermal method, sol-gel method, microemulsion method, electrodeposition method, reduction oxidation method, etc.) and combination method (such as hard template method, soft template method, grafting / modification-thermal decomposition method, etc.). However, due to the traditional cobalt oxide preparation technology and the subsequent high-temperature calcination treatment, it often leads to serious particle agglomeration, poor dispersion, unstable crystal structure, and difficulty in controlling grains and crystal forms. This has limited the widespread application of cobalt oxide materials to a certain extent. Therefore, researching and developing new cobalt oxide preparation technology and optimizing its physical and chemical properties are of great significance to promoting the development of lithium-ion batteries and related industries. Summary of the invention

[0005] The object of the present invention is to provide a preparation process of ultrafine and highly dispersed cobalt oxide, which is used to improve the dispersibility of cobalt oxide in the preparation process and improve the product quality.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0008] S1. Mix cobalt nitrate hexahydrate and deionized water, and stir for 15-20 minutes to obtain a cobalt nitrate solution;

[0009] S2, take the cobalt nitrate solution, add a dispersant, stir for 30-40 min, adjust the pH to 9.2-9.5, age at 5-10 ° C for 24 h, centrifuge, take the solid phase for washing, and obtain material A;

[0010] S3, taking the material A and placing it in a 100mL autoclave, adding anhydrous ethanol and n-butanol, stirring for 30-40min, purging the autoclave with nitrogen to drive out the air in the autoclave, sealing, pressurizing, heating and stirring for 30-40min, discharging the fluid in the autoclave, cooling the solid phase material in the autoclave, and obtaining material B;

[0011] S4, taking the material B, placing it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide.

[0012] As a preferred technical solution of the present invention, in step S1, the concentration of the cobalt nitrate solution is 0.2 mol / L.

[0013] As a preferred technical solution of the present invention, in step S2, the dosage ratio of the cobalt nitrate solution and the dispersant is 10-12 mL: 2-3 g.

[0014] As a preferred technical solution of the present invention, in step S3, the mass ratio of the material A, anhydrous ethanol and n-butanol is 8-10:30:20.

[0015] As a preferred technical solution of the present invention, in step S3, the pressurized heating refers to a pressure of 6.9-7.2 MPa and a temperature of 260-280°C.

[0016] As a preferred technical solution of the present invention, the preparation of the dispersant comprises the following steps:

[0017] N-dodecylsuccinic anhydride, L-tert-leucine and acetone are mixed and ultrasonically dispersed for 25-35 minutes, N,N-dimethyl-4-pyridinamine is added, and the mixture is stirred at 35-45° C. for 3-4 hours, 2-(2-butoxyethoxy)ethanol is added, and the mixture is stirred for 1-2 hours and the acetone is removed by rotary evaporation to obtain the dispersant.

[0018] As a preferred technical solution of the present invention, the mass ratio of N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 10-12:8-10:50:1-2:10-12.

[0019] As a preferred technical solution of the present invention, in step S4, the calcination refers to heating to 400-500° C. at a rate of 5-8° C. / min and calcining for 3-5 hours.

[0020] Beneficial effects of the present invention:

[0021] The invention discloses a preparation process of ultrafine highly dispersed cobalt oxide, by adding a dispersant, which reduces the surface tension of the cobalt oxide during its preparation, inhibits its agglomeration, increases its dispersibility, and makes the prepared cobalt oxide uniform in size and having good tap density. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0023] Example 1

[0024] A process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0025] S1, taking cobalt nitrate hexahydrate and deionized water, mixing, stirring for 15 minutes, to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0026] S2, taking the cobalt nitrate solution, adding a dispersant, stirring for 30 minutes, adjusting the pH to 9.2, aging at 5° C. for 24 hours, centrifuging, washing the solid phase, and obtaining material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 10 mL: 2 g;

[0027] S3, take the material A and place it in a 100mL autoclave, add anhydrous ethanol and n-butanol, stir for 30 minutes, purge the autoclave with nitrogen to drive out the air in the autoclave, seal and pressurize and heat and stir for 30 minutes, discharge the fluid in the autoclave, cool the solid phase material in the autoclave, and obtain material B; the mass ratio of the material A, anhydrous ethanol and n-butanol is 8:30:20; the pressurized heating refers to a pressure of 6.9MPa and a temperature of 260°C;

[0028] S4. Take the material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 400° C. at a rate of 5° C. / min and calcining for 3 hours.

[0029] The preparation of the dispersant comprises the following steps:

[0030] N-dodecyl succinic anhydride, L-tert-leucine and acetone are mixed, ultrasonically dispersed for 25 minutes, N,N-dimethyl-4-pyridinamine is added, and the mixture is stirred at 35°C for 3 hours. 2-(2-butoxyethoxy)ethanol is added, and the mixture is stirred for 1 hour and the acetone is removed by rotary evaporation to obtain the dispersant. The mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine and 2-(2-butoxyethoxy)ethanol is 10:8:50:1:10.

[0031] Example 2

[0032] A process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0033] S1, taking cobalt nitrate hexahydrate and deionized water, mixing, stirring for 18 minutes, to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0034] S2. Take the cobalt nitrate solution, add a dispersant, stir for 35 minutes, adjust the pH to 9.3, age at 8° C. for 24 hours, centrifuge, take the solid phase for washing, and obtain material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 11 mL: 2.5 g;

[0035] S3, take the material A and place it in a 100mL autoclave, add anhydrous ethanol and n-butanol, stir for 35 minutes, purge the autoclave with nitrogen to drive out the air in the autoclave, seal and pressurize and heat and stir for 35 minutes, discharge the fluid in the autoclave, cool the solid phase material in the autoclave, and obtain material B; the mass ratio of the material A, anhydrous ethanol and n-butanol is 9:30:20; the pressurized heating refers to a pressure of 7.1MPa and a temperature of 270°C;

[0036] S4. Take the material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 450° C. at 6° C. / min and calcining for 4 hours.

[0037] The preparation of the dispersant comprises the following steps:

[0038] N-dodecyl succinic anhydride, L-tert-leucine and acetone are mixed, ultrasonically dispersed for 30 minutes, N,N-dimethyl-4-pyridinamine is added, and the mixture is stirred at 40°C for 3.5 hours. 2-(2-butoxyethoxy)ethanol is added, and the mixture is stirred for 1.5 hours and the acetone is removed by rotary evaporation to obtain the dispersant. The mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine and 2-(2-butoxyethoxy)ethanol is 11:9:50:1.5:11.

[0039] Example 3

[0040] A process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0041] S1, taking cobalt nitrate hexahydrate and deionized water, mixing, stirring for 20 minutes, to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0042] S2, taking the cobalt nitrate solution, adding a dispersant, stirring for 40 minutes, adjusting the pH to 9.5, aging at 10° C. for 24 hours, centrifuging, washing the solid phase, and obtaining material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 12 mL: 3 g;

[0043] S3, take the material A and place it in a 100mL autoclave, add anhydrous ethanol and n-butanol, stir for 40 minutes, purge the autoclave with nitrogen to drive out the air in the autoclave, seal and pressurize and heat and stir for 40 minutes, discharge the fluid in the autoclave, cool the solid phase material in the autoclave, and obtain material B; the mass ratio of the material A, anhydrous ethanol and n-butanol is 10:30:20; the pressurized heating refers to a pressure of 7.2MPa and a temperature of 280°C;

[0044] S4. Take the material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 500° C. at 8° C. / min and calcining for 5 hours.

[0045] The preparation of the dispersant comprises the following steps:

[0046] N-dodecyl succinic anhydride, L-tert-leucine and acetone are mixed, ultrasonically dispersed for 35 minutes, N,N-dimethyl-4-pyridinamine is added, and the mixture is stirred at 45°C for 4 hours. 2-(2-butoxyethoxy)ethanol is added, and the mixture is stirred for 2 hours and then the acetone is removed by rotary evaporation to obtain the dispersant. The mass ratio of N-dodecyl succinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine and 2-(2-butoxyethoxy)ethanol is 12:10:50:2:12.

[0047] Comparative Example 1

[0048] The difference from Example 3 is that in the preparation of the dispersant, the mass ratio of N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 0:22:50:2:12.

[0049] Comparative Example 2

[0050] The difference from Example 3 is that in the preparation of the dispersant, the mass ratio of N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 22:0:50:2:12.

[0051] Comparative Example 3

[0052] The difference from Example 3 is that in the preparation of the dispersant, the mass ratio of N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine, and 2-(2-butoxyethoxy)ethanol is 24:10:50:2:0.

[0053] Comparative Example 4

[0054] The difference from Example 3 is that a process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0055] S1, taking cobalt nitrate hexahydrate and deionized water, mixing, stirring for 20 minutes, to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0056] S2, taking the cobalt nitrate solution, adjusting the pH to 9.5, aging at 10° C. for 24 h, centrifuging, washing the solid phase, and obtaining material A;

[0057] S3, take the material A and place it in a 100mL autoclave, add anhydrous ethanol and n-butanol, stir for 40 minutes, purge the autoclave with nitrogen to drive out the air in the autoclave, seal and pressurize and heat and stir for 40 minutes, discharge the fluid in the autoclave, cool the solid phase material in the autoclave, and obtain material B; the mass ratio of the material A, anhydrous ethanol and n-butanol is 10:30:20; the pressurized heating refers to a pressure of 7.2MPa and a temperature of 280°C;

[0058] S4. Take the material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 500° C. at 8° C. / min and calcining for 5 hours.

[0059] Comparative Example 5

[0060] The difference from Example 3 is that a process for preparing ultrafine highly dispersed cobalt oxide comprises the following steps:

[0061] S1, taking cobalt nitrate hexahydrate and deionized water, mixing, stirring for 20 minutes, to obtain a cobalt nitrate solution; the concentration of the cobalt nitrate solution is 0.2 mol / L;

[0062] S2, taking the cobalt nitrate solution, adding a dispersant, stirring for 40 minutes, adjusting the pH to 9.5, aging at 10° C. for 24 hours, centrifuging, washing the solid phase, and obtaining material A; the dosage ratio of the cobalt nitrate solution to the dispersant is 12 mL: 3 g;

[0063] S3, take the material A and place it in a 100mL autoclave, add anhydrous ethanol, stir for 40 minutes, purge the autoclave with nitrogen to drive out the air in the autoclave, seal and pressurize and heat and stir for 40 minutes, discharge the fluid in the autoclave, cool the solid phase material in the autoclave, and obtain material B; the mass ratio of the material A to the anhydrous ethanol is 10:30; the pressurized heating refers to the pressure of 7.2MPa and the temperature of 280°C;

[0064] S4. Take the material B and place it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide; the calcination refers to heating to 500° C. at 8° C. / min and calcining for 5 hours.

[0065] Performance Testing

[0066] The particle size of the cobalt oxide prepared in Examples 1-3 and Comparative Examples 1-5 was tested. The cobalt oxide powders prepared in Examples 1-3 and Comparative Examples 1-5 were tested by high-resolution scanning electron microscopy and tap density. The specific method is to disperse the sample under ultrasound, then drop the suspension of the suspended particles onto a sample table with a conductive glue using a capillary, spray molten gold liquid on it before the reaction, and finally place the sample table in a SEM instrument for scanning testing. The data are shown in Table 1.

[0067] Table 1

[0068] Average particle size Tap density (g / mL) Example 1 Uniform size, 32nm 2.31 Example 2 Uniform size, 28nm 2.35 Example 3 Uniform size, 31nm 2.32 Comparative Example 1 The size is relatively uniform, 82nm 2.07 Comparative Example 2 Relatively uniform size, 79nm 2.12 Comparative Example 3 The size is relatively uniform, 84nm 2.09 Comparative Example 4 Uneven size, 200nm 0.96 Comparative Example 5 The size is relatively uniform, 105nm 1.75

[0069] As can be seen from Table 1, the cobalt oxides prepared in Examples 1-3 of the present application have uniform size, excellent tap density, and a smooth surface.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for preparing ultrafine highly dispersed cobalt oxide, characterized in that: The following steps are involved: S1. Mix cobalt nitrate hexahydrate and deionized water, and stir for 15-20 minutes to obtain a cobalt nitrate solution; S2, take the cobalt nitrate solution, add a dispersant, stir for 30-40 min, adjust the pH to 9.2-9.5, age at 5-10 ° C for 24 h, centrifuge, take the solid phase for washing, and obtain material A; S3, taking the material A and placing it in a 100mL autoclave, adding anhydrous ethanol and n-butanol, stirring for 30-40min, purging the autoclave with nitrogen to drive out the air in the autoclave, sealing, pressurizing, heating and stirring for 30-40min, discharging the fluid in the autoclave, cooling the solid phase material in the autoclave, and obtaining material B; S4, taking the material B, placing it in a muffle furnace for calcination, grinding, and sieving to obtain the ultrafine and highly dispersed cobalt oxide.

2. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S1, the concentration of the cobalt nitrate solution is 0.2 mol / L.

3. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S2, the dosage ratio of the cobalt nitrate solution to the dispersant is 10-12 mL: 2-3 g.

4. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S3, the mass ratio of material A, anhydrous ethanol and n-butanol is 8-10:30:

20.

5. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S3, the pressurized heating refers to a pressure of 6.9-7.2 MPa and a temperature of 260-280°C.

6. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: The preparation of the dispersant comprises the following steps: N-dodecylsuccinic anhydride, L-tert-leucine and acetone are mixed and ultrasonically dispersed for 25-35 minutes, N,N-dimethyl-4-pyridinamine is added, and the mixture is stirred at 35-45° C. for 3-4 hours, 2-(2-butoxyethoxy)ethanol is added, and the mixture is stirred for 1-2 hours and the acetone is removed by rotary evaporation to obtain the dispersant.

7. A process for preparing ultrafine highly dispersed cobalt oxide according to claim 6, characterized in that: The mass ratio of the N-dodecylsuccinic anhydride, L-tert-leucine, acetone, N,N-dimethyl-4-pyridinamine and 2-(2-butoxyethoxy)ethanol is 10-12:8-10:50:1-2:10-12.

8. The process for preparing ultrafine highly dispersed cobalt oxide according to claim 1, characterized in that: In step S4, the calcination refers to heating to 400-500° C. at a rate of 5-8° C. / min and calcining for 3-5 hours.